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Flip-flop Boring Machine
I use a Champ Fond LB-21 boring machine for most of my line and construction boring. I've seen a number of machines like this and, like most things made in Taiwan, its a copy of one of them. Its a full cycle machine in that hitting the foot pedal pneumatically clamps the material to the table, starts the motor, pushes the drill head up until it hits a pneumatic limit switch, lets the head drop down, releases the air clamps and turns off the motor. It has quick change collets and a hydraulic brake for through boring. It came with side fences and a rudimentary back fence. I ended up tossing the side fences and use a custom back fence for all boring.
The machine has a pivoting 21 spindle head that pneumatically flips up for end boring and flops down for line/face boring. For standard line and construction boring, the fence stays put and the head is moved via a crank that has a digital position indicator. My final setting of the head position is always done in a clockwise direction to insure accurate and consistent positioning. I mark all such adjusters in my shop to indicate which direction the movable part moves when the adjuster is turned in a clockwise direction. The depth of the bored holes is determined by the position and setting of a turret depth stop. I've supplemented the turret stop with a sleeve that enables and disables the hydraulic brake. The sleeve is the only change I need to make to switch from standard depth boring to through hole boring.
I made my fence with 8020 T-slot extruded aluminum and the stops/connectors from heavy gage stock aluminum profiles. While I seldom need to move the fence, it can be moved side to side and backwards in 16mm increments. The stock fence position allows for face boring 0-38mm from the fence and all end boring. While I was happy with my push stop design (push the board against an unused stop and it pivots out of the way), I wasn't getting the consistency I wanted when doing construction boring. I came up with a single piece stop that has an adjustable post that the material being bored butts against. I located the post so that it is in the same relative position when face and end boring. See also: Construction Boring Stops
I made my fence with 8020 T-slot extruded aluminum and the stops/connectors from heavy gage stock aluminum profiles. While I seldom need to move the fence, it can be moved side to side and backwards in 16mm increments. The stock fence position allows for face boring 0-38mm from the fence and all end boring. While I was happy with my push stop design (push the board against an unused stop and it pivots out of the way), I wasn't getting the consistency I wanted when doing construction boring. I came up with a single piece stop that has an adjustable post that the material being bored butts against. I located the post so that it is in the same relative position when face and end boring. See also: Construction Boring Stops